Catalytic Ozonation Of Refractory Organic Pollutants By Supported Ferrous Oxide

Heterogeneous catalytic ozonation has been received increasing attention in recent years because of its potentially higher effectiveness in the degradation and mineralization of refractory organic pollutants and lower negative effect on water quality. However the lack of in-depth researches on the relationship between structural morphology and catalytic activity hinders the development of heterogeneous catalytic ozonation. The formation of bromate during catalytic ozonation progress should be intensively studied. Additionly, up-to-date, there is none suitable catalytic material can fulfill the demands of practical process and commercialization for water treatment. In this paper, Ferrous oxide was supported on ordered mesoporous zirconia by wet impregnation method. The XRD, FTIR, UV-Vis techniques were used for characterizations of this material. Ozone decomposition,TOC removal and bromate formation during the catalytic ozonation process were studied. The main research contents and results are listed as followed:(1)Mesoporous ZrO₂ has large surface area and rich surface hydroxyls. The introduction of FeOx did not change the distribution of the pore diametersand the BET surface area of ZrO₂ indicating the high dispersion of FeOx. FeO_X/ZrO₂ may have excellent catalytic performance due to its large surface area, porous structure, rich surface hydroxyls, and high electron transfer capacity.(2)The catalyst enhanced the mineralization of 2,4-dichlorophenoxyacetic acid (2,4-D) by the formation of ?OH radicals resulting from the catalytic decomposition of ozone. About 90% of TOC was removed at a reaction time of 40 min in the presence of the catalyst. Compared with ozonation, catalytic ozonation enhanced the formation of bromate. Bromate formation can be minimized by controlling reaction time and pH value.(3)FeO_X/ZrO₂ did not enhance the decomposition of ibuprofen and clofibric acid, but significantly increased the TOC removal rate. Compared with ozonation, catalytic ozonation enhanced the formation of bromate. The optimal reaction time is 10 min.